How To Choose The Right Check Valve?

An essential element in the design of water and wastewater pumping systems is the proper selection of pump discharge check valves, which are designed to automatically open to allow positive flow and automatically return to the closed position to prevent pump backflow. Not operating. Another often overlooked feature is the valve's ability to minimize energy consumption.

 

But just as important, valves should protect pumping systems and piping from pressure fluctuations caused by sudden closures. Every pump station designer has witnessed check valve slamming, which is caused by the sudden stop of backflow through the closed check valve. To prevent slamming, automatic check valves must be closed very quickly or slowly using an oil buffer device. Check valves are generally classified into three categories.

Ductile iron Rubber Disc Check Valve

Even with knowledge of all the various categories and types of check valves, it is still difficult to reasonably decide which type of check valve is best for a given application. Buying a check valve is similar to buying a car. There are many to choose from, and because each model is designed to meet different needs, the best car is not necessarily the fastest. You may be looking for compactness, high performance, low cost, or advanced features; however, just as there is a car that best meets your requirements, there will likewise be a check valve that best meets your requirements.

 

In order to match the best type of check valve to a given application, several operating parameters must be defined. These selection criteria may or may not be important for a given application, but they all play a role in the selection process. The first criterion is the initial cost. The purchase cost of valves varies widely and should also include installation costs. The initial cost of a check valve should consider its lay length and the length of piping required to lay it, as well as the cost of installation and support.

 

Next is the cost of maintenance. It is usually safe to say that the more moving parts in a valve, the greater the maintenance needs. The manufacturer's recommended maintenance schedule should be reviewed and factored into the valve's life cycle cost.

 

The third is head loss and energy costs. The head loss of a valve can be converted to an annual energy cost associated with the power required by the pump to overcome the additional head loss of the valve. The energy cost of some valves can be much higher than their initial cost.

 

The next criterion is the non-manifold characteristic. The closing characteristics of the valve must be matched to the dynamics of the pumping system.

 

The last is fluid compatibility, as the piping medium is critical to the selection of a check valve. The rule of thumb regarding check valve selection and suspended solids is that the higher the concentration of suspended solids, the more care is required when selecting a check valve.

 

Now that a better understanding of check valve types and their performance characteristics is available, a sound decision-making process can be used to select the application-specific check valve that meets individual preferences and system parameters. There is no one check valve that is best suited for all applications. Each installation requires different weights to be assigned to the selection criteria, so there are applications that apply to all available check valves.